The production of compositions comprising proteins for biopharmaceutical applications involves the use of upstream process technologies (e.g., cell culture) and downstream process technologies (e.g., protein purification) that are known to produce proteins exhibiting varying levels of protein variants and impurities within the composition. Such protein variants include, but are not limited to, the presence of charge variants (e.g., basic variants and acidic species, including variants) and process-related impurities. For example, in monoclonal antibody (mAb) preparations, charge variants can be detected by various methods, such as ion exchange chromatography, for example, WCX-10 HPLC (a weak cation exchange chromatography) or IEF (isoelectric focusing). Because of their similar chemical characteristics to the antibody product molecules of interest, reduction of charge variants is a challenge in monoclonal antibody production.
Reduction of charge variants and/or product- or process-related impurities is particularly advantageous in the context of commercially produced recombinant biotherapeutics, as they have the potential to impact numerous product characteristics, including, but not limited to, product stability, product safety and product efficacy. Accordingly, there remains a need in the art for low acidic species compositions and high-efficiency methods of producing protein compositions, e.g., antibodies, having low levels of acidic species.